Electric-driven tool.



PATENTBD MAY 5, 1908.

A. P. CARVER. ELECTRIC DRIVEN TOOL. APPLICATION 211.31) mm. a, 1907.

wm ron, Mn Z'C'aru6r; 8) f Arm/mus.

- has been the magnetizing of the hard metal asmaybe found desirable.

The hammer is wound UNITEDsTA ES PATENT OFFICE.

ALLEN F. CARVER, on NEW roan, N. Y.-

ELECTRIC-DRIVEN TOOL.

No. ssae'rs.

Specification of Letters Patent. I I

Patented May 5, 1908.

Application filed February 5 1907. Serial No..355,888.

Tdall whom it may concern.

Be it known that I, ALLEN F. CARVER, a

citiitenof the United States, residing at New York, in the county of New York and State of New York, have invented new and useful Im 'rovemen-ts in Electric-Driven Tools, of which the following is a specification.

My invention relates to electric reci r0- eating tools and devices of all kinds, suc as riveting, chipping and calki hammers,

rock drills, etc., and has for its object the repelling of the operatingparts of thehamrner and'the relief of these parts of magnetic attraction which would otherwise impair their working, also means for more efiectually pre-' venting sparking in. certain contact points all of which will be hereinafter more fully eirplained in this specification, set forth in the claimsahd illustrated in the drawings.

Figure 1 1s a diagrammatic view of ahammer with itsoperating adjuncts and fits electric circuits. Fig. 2 is a sectional view of the tool holding chuck and the shank of the drill. Fig. 3 is a face view of the chuck.

A seriousobjection in. electric hammers partswhich are necessary in their construction and'the consequent attraction of these arts to each other so that their rapid action is seriously impaired and the utihty of the tool reduced to a minimum and' it is for the,

purpose of overcoming these oh'ect-ionsthat the present invention is desire .and also to prevent sparking of certain parts-whenthe circuit is'brokenand as these In the drawing the hammers-isfovided" with the usual tool 6 and plun'ger 7, t e latter having behindit a spring or other cushion 8,, to prevent too suddena return of the plunger to the rear of the hammer and'a battering action' at that end of the tool. v This spring is inclosed in a casing 9 or otherwise arranged 'th a plurality of coils, but'preferably two coils 10 and 11, the.

latterbeing smaller than the former on account of less work being required from it and as shown in the drawings these coils are wound in the same direction but the electric connections .are so made as to'produce like magnetic polarity-at their adjacent ends the common return wire 21 is connected to the inside of coil 10 and to the outside end of coil 11. By this simple and efficient means the inormalposition. springs 15, 16, 17 and 18which are adapted q I reaks are'very frequent and numerous it leads to serious, wearing away of said contacts.

, Flunger and shank are so magnetized with ke polarity that any attraction or sticking ,of these parts is avoided during thereturn stroke. i i The operation of the hammer is controlled by a plunger 12 having a button 13 to operate same and a sprin -14 to return, it to its TlllS plunger controls four to control certain currents which influence the hammer to accomplish the results sought to be obtained. The source'of electricity is illustrated by the points 19 and 20, the point 19 suppl ing the hammer with the current b means 0 the wire 21 which is connected wit the interior turn of coil 10 and the exterior turn of coil 11, this circuit bein open until thebutton .13 is depressed'as wi 1 be hereinafter explained. A connection 22 leads from this line to the spring 15 and when it is de sired to start the hammer, by pressing the ,plu er and bringing the contact 15 and 16 toget er a circuit is setup in the direction indicated by the arrows H and which includes a coil 24 surrounded by a'separate coil 23. 'Thesecoils contain and energize a core 25 which attracts an armature 26 and closes the contacts 27 establishing a circuit indicated by'the arrows which passes throu h the coil '23 and holds the armature 26 more rml against the'core 25 .and'alsopasses throng the shaft 41-ofthe cornmu'tator28 the seg-' ment45 andbrush'46. When the plunger 12 is "further depressedthe contacts on the spring 15, 16and lZ are closed'and a circuit is createdlwhichincludes-in it an ele'ctro-mag- 32 a greater distance away tator. It-rnay be desirable to regulate: this distance .or period for theflow of current through the coils and-in order to'accornplish this I ro.vide the stem" 36 of the core 33 .with

a toot 37 which is adapted to come in con- 40. Instead of one tooth 37'severalof these .maybe arranged on the stem with-an armature, pawl and operating magnet and contact with a pawl-38 carried by an armature A 39 which is actuated by an electrmmagnet' when the plunger 12 is de ressed tact spring for the magnet .added to the switch controlled by the operator of the tool so thata step-by-step to permit the increase of the period oiflow of the current. This electro-magnet 40 is controlled-by the contact on the sprin action may be arranged ar enough closesacircuit including t :selectro-magnet and elevates the pawl38 so that the-solenoid accomplishing thisobject. I

Iton'1'3 is released the-reverse order. takes place, except in case the se mnt45' is in contact with the brush 46.- tion exists the armature;

2ev will be held. by

the core and he'currentcontinues to flow. "20' a: the commutator revolves so as to br ng the opening in'ring 45 to in the mainl ne to the commutaton- When the point of contact between'this ring 45 and brush 46, the coil 23 will be dener 'zed as there is now no magnetism induce in core 25 by either coil 24 or coil 23 the armature 25 will be released breaking the. main line to the commutator at 27. No sparkin' can occur at the contact points 27 when a ove action takes place as the break in the'ring'45 isso placed relative to the segment 28 that coil 23 can never be deenergized as long as the segment 28 is feedingcurrent to brushes 34, 31, 42,43, 35 and As illustrated in the'drawing the segment 28- is. shown just-about to leave the brushes 31 'andv34, the commutator moving in the direction shown by the arrow H,

but when it finally does leave these brushes the current stillflows throu brushes 42 and 43 and t e resistance coil 44. As the wheel 28 revolves still further the segment 28 comes lnto'contact with brushes 35 I and 32 allowing the current to flow through coil 11, 45

end of the lunger 7 which as these brushes control the current passing through this coil and as, the segment is still making contact with the brush 43 there is still a greatly reduced current flowing through coi 10 in consequence of'the resistancecoil 44 being in that circuit. When the above action is taking place the end of the tool 6 will be of the same clarity as the is t en in contact with it an the plunger and tool will not be attracted towards each otherbut re elled, and the more stron ly energized coi 11 is able to retract the unger 7 from the shank of the tool so as to e ready for another blow when the coil 11 is denergized and coil 10 is energlilzled to its full strength again.

W e I have not shown modifications for the various means above described for. ac-

complishing these results it is obvious that various means-may be employed without departin from the essential features above describe 18which I "le this'condi' Y 10 reducing the current and h the coil 10 by the through and shown.) For instance that by.

mcreasing U1 uuuuumuu w ivvwwuwthe, coil 44 the relative coils, 10 and 11 at which t e plunger andtool shank will release perfectly can be varied.

In an electric tool driver proportioned as shown, the tool shank is partly within. the

field of coil 10 and the plunger 7 isalso a partly coil 10 is energized full strength and end of within the field of coil 10, when the plun er 7 is in such a position that it is sepa rate from the end 0 the tool shank, there are set up lines of magnetic force tending to makethe ends of the plunger and the tool shank of opposite polarity, and the plunger will be attracted with great force towards the tool shank. As the commutator revolves a resistance 44 is cut in in series with this coil magnetic intensity of the lines of force. v plunger 7 and the tool shank are still of oposite polarity and stick to ether. If now,

owever, coil '11 is sudde y energized full stre th at the same time that coil 10 is wea y energized, the magnetic lines of force induced by coil 11 which are of opposite olarity to those induced by coil 10, will i ow through lunger 7 until they meet the lines of-forceowing in .the op osite direction in ,tool shank, due to action oicoil 10. This action is possible because as coil 10 is now relatively weak to coil 11, coil 11 is able to reverse the polarit of that art of plunger 7 lying within co' 10. Co' 10, however, is kept strong enough to retain the original polarit of tool shank, and hence thereleasing of p unger from toolshank. When this occurs the magnetic polarity of the end of tool shank, and end of the plunger 7 will be alike and will repel each other and the coil 11 will retract the plun er 7 which is then in a position to be acte upon for another forward movement towards tool-shank when the coil 11 is deenergized and coil 10 is energized full strength-again.

What I claim as new and desire to secure by Letters Patent is: l

1. In an electric tool driver, the combination with a plunger," of coils adapted to imart a different polarity to the plunger when it has about completed its stroke, and means connectedfwith t e tool for reducing the current in one coil while a greater current flows the other coil.

2. an electric tool driver, the combination with a plunger, of two coils adapted to change the polarity of the plunger at the end of itsstroke, and means connected with the tool for alternating the magnetic strength from one coil to the other for every stroke of said lunger.

3. u an electric tool driver, the combination with a plunger, of coils of opposite magnetic polarity, and means for changing the relative stren ths of the magnetic polarities for every stro e of said plunger.

The end of the plosition within this seas-rs 4. In an electric tool driver, means under the control of the operator for electrically varying the relative eriod of energization and denergizaticn' of t e coils.

5. In an electric tool driver, the combina tion with a'lplunger, of a tool 0 erated by the plunger," co s enveloping the pun er and actuating same, electric circuits incuding the coils, means for alternating the current strength through the circuits, and means for varyin the period of passage of thecurrent throu the circuits. c 4 6. 11 an electric tooldriver, the combina tion with aplunger, of a tool operated by the plunger, coils enveloping, the plunger and actuating same, electric circuits including the coils, means for alternating the current strength through the circuits, and means for electrically varyin the period of passage of the current throng the circuits.

7'. In an electric tool driver, the combina-' tion of the tool, of a lunge'r operating upon same, coils surroun ing the plun er and actuating it, electric circuits, means orvary 'ing the period'of flow of the current through the circuits and means for varying the polarity. of the plunger and the tool so as to cause them torepel each other.

8. In an electric tool driver, the combination with the tool, of a plunger operating upon same, coils surrounding the plunger and one end of the tool and adapted to roduce repelling polarity in the tool and p unger-when the coils are energized together, a.

commutator with'brushes adapted to close the circuits leading to the coils, an electro magnet rovided with means for altering the relations ip between the brushes, an electromagnet adapted to operatea switch to close' the circuit operating the tool, a second electro-magnet wound around the latter-electro.

magnet and adapted to hold; the switch in its closed position and a switch under the control of the operator and adapted to close the circuits controlling these electr'o-magnets and on further movement to close the circuit of the electro-magnet controlling the brushes.

9. In an electrictool driver, the combination with constantly energized coilsjadapted.

to produce opposite olarity, of electrical means for varying the ength oftime that the current flows through the coils, adjusting means for the above controlling means and a circuit closing el'ectro-magnet working in conjunction with aseparate coil on same, a magnet for keeping the switch closed and a plunger with a plurality of contact carrying springs which are operated upon by the plun ger to close and operate the circuits control- 4 ling themeans for the flow oielectricity, the

adjusting means .and the closing circuit magnet.

v 10. In an electric tool driver, the combina tion with a plunger of a tool 0 erated thereby, constantly ener ized coi s ada ted to produce diiierent po arity surroun mg. the plunger, an electric circuit embracing the coils, an electro-magnet in the circuit, a switch'controlled by the operator adapted to close the circuit and energize the electromagnet, a second electric circuit including an armature actuated by the electro-magnet, an interrupter in the circuit, a second electro magnet in the circuit and resistance coils adapted to be thrown in to the coils when a releasing action is desired between the plunger andtool.

. "11. In an electric tool driver, the com-bination with a plunger, of a tool operated thereby, constantly energized coils surroundingthe'plun er and adapted to reciprocate the same an to Iproduce different polarity'and means contro ed by the operator'of the tool for varying the intensity of the current to increase'ordiminish the force of the blow.

. 12.,In combination with an electric' tool driver, an ,electro-magnet switch consisting of a stationary core, a coil wound on same,

an armature adapted to be acted on by said core and coil, and a switch in the main circuit operated-by the movement of said arma ture, said electro-magnet switch controlled by another switch under the control of the operator of the tool, v 13. In combination with an electric tool driver, an electro-magnetic switch. wound with a double winding of same polarity controllingv the main line, and adapted to open the main line without serious sparking the switch contacts, substantially as described.

14. In combination with an electric tool driver an electro-magnetic switch controlling the main line wound with two coils'oi same polarity one under the control of operator of tool driver, and thootl er controlled by such means'tliat it will hold said magnetic switch closed independent of action of coil.

under control of operator,and only allowing? Witnesses: 4

MAE-1W. CLINTON, JA Es F. DUHAMEL. 

